Electron-phonon interaction in the V2+:CsCaF3 laser crystal: geometry of the [VF6]4− complex in the 4T2g excited state

The dynamic T⊗e Jahn-Teller effect in the 4T2g lowest excited state of the V2+ ion in the CsCaF3 laser crystal is considered using an analysis of the ligands displacement due to the combined effect of the a1g and eg normal modes of the octahedral [VF6]4− complex. The net result of these vibrations is both axial and equatorial expansion by 0.02 and 0.12 Å, respectively. Electron-phonon coupling constants for the a1g, eg, t2g normal modes were estimated using the experimental value of the crystal field strength Dq. The contour plot of the potential energy surface in the 4T2g excited state was drawn; from that plot, the Jahn-Teller stabilization energy for the studied system was estimated to be 368.6 cm−1.